JP7665448B2 - Motors and Drive Units - Google Patents

Description

The present invention relates to a motor and a drive device.

Conventionally, there is known a static elimination device that eliminates static electricity from the shaft of a motor of a drive device. For example, a charge dissipation assembly serving as a static elimination device is disposed between the shaft and the housing of the motor, and contacts the radially outer surface of the shaft to earth the shaft voltage (see, for example, JP 2005-124391 A).

JP 2005-124391 A

However, if foreign matter adheres to the static eliminator, the efficiency with which the static eliminator eliminates static electricity from the shaft may decrease. For example, in an in-vehicle drive system, lubricating oil and refrigerant used to cool the motor may adhere to the static eliminator. In this case, the conductivity of the static eliminator may decrease, making it difficult to maintain good electrical conduction between the shaft and the housing.

The present invention aims to maintain good electrical connection between the shaft and the housing.

An exemplary motor of the present invention includes a shaft, a rotor, a stator, a bearing, a housing, a first static eliminator, and a seal member. The shaft has a first shaft extending axially along a rotation axis. The rotor is fixed to the shaft and is rotatable about the rotation axis. The stator faces the rotor with a radial gap. The bearing rotatably supports the shaft. The housing accommodates the rotor, the stator, and the bearing. The shaft further has a second shaft. The second shaft extends from the first shaft in one axial direction. The housing has a bearing holder and a static eliminator holder. The bearing holder has an opening through which the first shaft is inserted and holds the bearing. The static eliminator holder holds the first static eliminator and covers at least a portion of the opening. The static eliminator holder has a seal holder. The seal holder is disposed radially outward from the second shaft and holds the seal member. The first static eliminator electrically connects the second shaft and the static eliminator holder. The seal member seals between the second shaft and the seal holder and is positioned on the other axial side of the first static eliminator.

An exemplary drive device of the present invention includes the above-mentioned motor and a power transmission device. The power transmission device transmits the power of the motor to a drive shaft.

The exemplary motor and drive device of the present invention can maintain good electrical connection between the shaft and the housing.

FIG. 1 is a conceptual diagram showing an example of the configuration of a drive device. FIG. 2 is an enlarged conceptual diagram showing an example of the configuration of a main part of the drive device according to the embodiment. FIG. 3 is a schematic diagram showing an example of a vehicle equipped with the drive device. FIG. 4 is a schematic diagram showing another configuration example of the first shaft. FIG. 5A is a diagram showing an example of contact between the second shaft and the first static eliminator. FIG. 5B is a diagram showing another example of contact between the second shaft and the first static eliminator. FIG. 6A shows a first arrangement example of the second shaft through-hole in the shaft cover portion. FIG. 6B shows a second example arrangement of the second shaft through-holes in the shaft cover portion. FIG. 6C shows a third example arrangement of the second shaft through-holes in the shaft cover portion. FIG. 7 is a schematic diagram showing another example of the arrangement of the first static eliminator. FIG. 8 is a schematic diagram showing another example of the configuration of the seal holder. FIG. 9 is an enlarged conceptual diagram showing an example of the configuration of a main part of a drive device according to a first modified example. FIG. 10 is an enlarged conceptual diagram showing an example of the configuration of a main part of a drive device according to a second modified example. FIG. 11 is an enlarged conceptual diagram showing an example of the configuration of a main part of a drive device according to a third modified example.

An exemplary embodiment is described below with reference to the drawings.

In this specification, the direction parallel to the rotation axis J1 of the motor 1 is defined as the "axial direction" of the drive unit 100. As shown in FIG. 1, the motor 1 side is defined as one axial direction D1, and the power transmission unit 3 side is defined as the other axial direction D2. The radial direction perpendicular to a specific axis is simply referred to as the "radial direction", and the circumferential direction centered on the specific axis is simply referred to as the "circumferential direction". Furthermore, in this specification, a "parallel direction" includes not only completely parallel directions, but also directions that are approximately parallel. And "extending along" a specific direction or plane includes extending in a direction tilted within a range of less than 45° with respect to the specific direction, in addition to extending strictly in the specific direction.

<1. Driving device 100>
FIG. 1 is a conceptual diagram showing a configuration example of the drive device 100. FIG. 2 is a conceptual diagram showing an enlarged configuration example of a main part of the drive device 100 according to the embodiment. FIG. 3 is a schematic diagram showing an example of a vehicle 300 equipped with the drive device 100. Note that FIG. 1 and FIG. 2 are merely conceptual diagrams, and the arrangement and dimensions of each part are not necessarily the same as those of the actual drive device 100. Also, FIG. 2 is an enlarged view of a portion II surrounded by a dashed line in FIG. 1. Also, FIG. 3 conceptually illustrates the vehicle 300.

In this embodiment, as shown in FIG. 3, the drive unit 100 is mounted on a vehicle 300 that uses at least a motor as a power source, such as a hybrid vehicle (HV), a plug-in hybrid vehicle (PHV), or an electric vehicle (EV). The drive unit 100 is used as a power source for the vehicle 300. The vehicle 300 has the drive unit 100 and a battery 200. The battery 200 stores power to be supplied to the drive unit 100. In the case of the vehicle 300, the drive unit 100 drives the left and right front wheels. Note that it is sufficient that the drive unit 100 drives at least one of the wheels.

As shown in FIG. 1, the drive device 100 includes a motor 1 and a power transmission device 3. The power transmission device 3 transmits the power of the motor 1 to the drive shaft Ds. According to the configuration of the drive device 100 described below, the electrical connection between the shaft 2 of the motor 1 and the housing 4 can be maintained well. Therefore, electrolytic corrosion caused by a current generated by potential fluctuations occurring within the shaft 2 of the motor 1 can be stably suppressed or prevented.

<2. Motor 1>
The motor 1 is a DC brushless motor. The motor 1 is a drive source for the drive device 100, and is driven by power from an inverter (not shown). As shown in Fig. 1, the motor 1 includes a rotor 11, a stator 12, a shaft 2, a housing 4, a fluid circulator 5, a rotation detector 6, and a first static eliminator 7. Details of the housing 4 will be described later.

<2-1. Rotor 11>
The rotor 11 is fixed to the shaft 2 and is rotatable about a rotation axis J1. More specifically, the rotor 11 is fixed to a radially outer surface of a first shaft 21, which will be described later. The rotor 11 rotates when electric power is supplied to the stator 12 from a power supply unit (not shown) of the drive device 100.

The rotor 11 has a rotor core 111 and magnets 112. The rotor core 111 is formed, for example, by laminating thin electromagnetic steel sheets. The rotor core 111 is a cylindrical body extending along the axial direction, and is fixed to the radially outer surface of the first shaft 21. A plurality of magnets 112 are fixed to the rotor core 111. The multiple magnets 112 are arranged in the circumferential direction with alternating magnetic poles.

The rotor core 111 also has a rotor through hole 1111. The rotor through hole 1111 penetrates the rotor core 111 in the axial direction and is connected to the first shaft through hole 201. The rotor through hole 1111 is used as a flow path for fluid F. In this embodiment, the fluid F is a lubricating liquid that lubricates the bearings of the drive unit 100, the power transmission unit 3, and the like, and is, for example, oil such as ATF (automatic transmission fluid). The drive unit 100 includes the fluid F. The fluid F is also used as a refrigerant that cools the stator 12 and the bearings 4211, 431 described below.

When the rotor 11 rotates, the fluid F flowing through the hollow portion 212 of the first shaft 21 can flow into the rotor through hole 1111 via the first shaft through hole 201. The fluid F that flows into the rotor through hole 1111 can flow out of the rotor core 111 from both axial ends of the rotor through hole 1111. The outflowing fluid F flies toward the stator 12, for example, cooling the coil portion 122 (particularly the coil end 1221) described below. The outflowing fluid F also flies toward the bearings 4211, 431 that rotatably support the first shaft 21, lubricating and cooling the bearings 4211, 431.

<2-2. Stator 12>
The stator 12 faces the rotor 11 with a radial gap therebetween. The stator 12 is disposed radially outward of the rotor 11 and rotates the rotor 11. The motor 1 is an inner rotor type in which the rotor 11 is rotatably disposed radially inward of the stator 12.

The stator 12 has a stator core 121 and a coil portion 122. The stator 12 is held in a first housing cylindrical portion 41, which will be described later. The stator core 121 has a plurality of magnetic pole teeth (not shown) that extend radially inward from the inner peripheral surface of the annular yoke. The coil portion 122 is formed by winding a conductor around the magnetic pole teeth via an insulator (not shown). The coil portion 122 has coil ends 1221 that protrude from the axial end faces of the stator core 121.

<2-3. Shaft 2>
The shaft 2 extends in the axial direction along the rotation axis J1. The shaft 2 supports the rotor 11 and is rotatable around the rotation axis J1. The shaft 2 is rotatably supported by the housing 4 via bearings 4211, 4221, 431, and 4611, which will be described later. In this embodiment, the bearings 4211, 4221, 431, and 4611 are ball bearings, respectively. However, the types of the bearings 4211, 4221, 431, and 4611 are not limited to this example. For example, at most three of these may be bearings other than ball bearings (e.g., sliding bearings, etc.).

The shaft 2 has a first shaft 21, a second shaft 22, a first shaft through hole 201, and a second shaft through hole 202. The first shaft 21 and the second shaft 22 are conductive and made of metal in this embodiment.

<2-3-1. First shaft 21>
The first shaft 21 is cylindrical and extends axially along the rotation axis J1. As described above, the shaft 2 has the first shaft 21. A fluid F flows inside the first shaft 21. The fluid F is supplied to the stator 12 and the bearings 4211, 431, etc. through the first shaft through-hole 201 in response to the rotation of the shaft 2, and can cool them.

The first shaft 21 may be split at the middle in the axial direction. If the first shaft 21 is split, the split first shaft 21 may be connected, for example, by spline fitting. Alternatively, the split first shaft 21 may be connected by a screw coupling using male and female threads, or may be joined by a fixing method such as press fitting or welding. When using a fixing method such as press fitting or welding, serrations that combine concave and convex portions extending in the axial direction may be used. With this configuration, it is possible to reliably transmit rotation between the split first shafts 21.

The first shaft 21 has a shaft tube portion 211. The shaft tube portion 211 extends in the axial direction and surrounds the rotation axis J1. The first shaft 21 further has a hollow portion 212 and an inlet 213. The hollow portion 212 is a space surrounded by the inner circumferential surface of the shaft tube portion 211 and is disposed inside the shaft tube portion 211. The inlet 213 is an opening at the end of the shaft tube portion 211 on the other axial direction D2 side, and is connected to an oil passage 465 of the gear cover portion 46 described later. Fluid F flows from the oil passage 465 into the hollow portion 212 via the inlet 213.

The first shaft 21 further has a shaft lid portion 214. The shaft lid portion 214 is disposed on one axial side D1 of the first shaft 21. The shaft lid portion 214 extends radially outward from the rotation axis J1. In this embodiment, the shaft lid portion 214 is separate from the first shaft 21 as shown in FIG. 2. However, this is not limited to the example, and the shaft lid portion 214 may be integral with the first shaft 21 (see FIG. 4).

Preferably, the first shaft 21 has a cylindrical peripheral wall portion 215. The peripheral wall portion 215 protrudes in one axial direction D1 from the end portion on one axial direction D1 side of the shaft cylindrical portion 211. The tip portion of the seal holder 442 described later is inserted into the peripheral wall portion 215.

Preferably, the first shaft 21 has a step 216. The shaft cover 214 fits into the step 216. The step 216 is disposed on the inner circumferential surface of the first shaft 21 at the end of the first shaft 21 on the axial side D1. The step 216 includes a first opposing surface 2161 and a second opposing surface 2162. The first opposing surface 2161 axially faces the end of the shaft cover 214 on the axial side D2. The second opposing surface 2162 extends from the radial outer end of the first opposing surface 2161 to the axial side D1 and radially faces the radial outer end of the shaft cover 214. In this embodiment, the first opposing surface 2161 extends radially outward from the inner circumferential surface of the shaft tube portion 211. The second opposing surface 2162 is a part of the inner circumferential surface of the peripheral wall portion 215. However, without being limited to this example, the second opposing surface 2162 does not have to be a part of the inner circumferential surface of the peripheral wall portion 215, and may be, for example, a part of the inner circumferential surface of the shaft tube portion 211. In this way, when assembling the shaft 2, the shaft cover portion 214, which is separate from the first shaft 21, can be abutted against the first opposing surface 2161, thereby positioning the shaft cover portion 214 relative to the first shaft 21. This improves the ease of assembling the shaft 2.

Note that the above examples do not exclude configurations in which the first shaft 21 does not have at least one of the peripheral wall portion 215 and the step 216.

<2-3-2. Second shaft 22>
The second shaft 22 extends in one axial direction D1 from the first shaft 21. In this embodiment, the second shaft 22 extends in one axial direction D1 along the rotation axis J1 from the shaft cover portion 214. The outer diameter of the second shaft 22 is smaller than the outer diameter of the first shaft 21 (the shaft tube portion 211), and is smaller than the inner diameter of the shaft tube portion 211, for example.

The first static eliminator 7 contacts the second shaft 22. FIG. 5A is a diagram showing an example of contact between the second shaft 22 and the first static eliminator 7. FIG. 5B is a diagram showing another example of contact between the second shaft 22 and the first static eliminator 7. Preferably, as shown in FIG. 5A, the first static eliminator 7 contacts at least a portion of the circumferential area of the radially outer surface of the second shaft 22. In this way, compared to a configuration in which the first static eliminator 7 contacts the end of the second shaft 22 on one axial side D1, for example, there is no need to secure space on one axial side D1 of the second shaft 22 to place the first static eliminator 7. Therefore, the increase in the axial size of the motor 1 can be suppressed, which contributes to the miniaturization of the motor 1 and the drive device 100.

When the first static eliminator 7 contacts a portion of the circumferential area of the radially outer surface of the second shaft 22 as shown in FIG. 5A, the sliding area of the first static eliminator 7 against the second shaft 22 when the shaft 2 rotates can be made smaller. Therefore, even if the first static eliminator 7 wears due to sliding, the amount of wear can be reduced, and the amount of wear powder generated can also be reduced.

In addition, when the first static eliminator 7 contacts the entire circumferential area of the radially outer surface of the second shaft 22 as shown in FIG. 5B, the contact area of the first static eliminator 7 with the second shaft 22 can be made larger. This makes it possible to reduce the electrical resistance between the two, thereby further improving the static elimination efficiency of the first static eliminator 7.

<2-3-3. First shaft through hole 201>
The first shaft through-hole 201 penetrates the first shaft 21 in the radial direction. As described above, the shaft 2 has the first shaft through-hole 201. In detail, the first shaft through-hole 201 is disposed in the shaft cylindrical portion 211 and penetrates the shaft cylindrical portion 211 in the radial direction. When the shaft 2 rotates, the fluid F in the first shaft 21 flows out of the first shaft 21 from the hollow portion 212 through the first shaft through-hole 201 to the outside of the first shaft 21 by centrifugal force.

In this embodiment, as shown in FIG. 1, the first shaft through hole 201 is positioned further in the axial direction D2 than the end of the rotor 11 on the axial side D1, and further in the axial direction D1 than the end of the rotor 11 on the axial side D2, and is connected to the rotor through hole 1111 as described above.

However, without being limited to the example shown in FIG. 1, at least one first shaft through hole 201 may be disposed on the axial side D1 from the bearing 4211 and on the axial side D2 from the end of the rotor 11 on the axial side D2. Alternatively, at least one first shaft through hole 201 may be disposed on the axial side D1 from the end of the rotor 11 on the axial side D1 and on the axial side D2 from the shaft cover portion 214. In this way, the refrigerant (i.e., fluid F) flowing inside the shaft tube portion 211 can be made to flow directly toward the stator 12, the bearings 4211, 431, etc. through at least one first shaft through hole 201.

<2-3-4. Second shaft through hole 202>
The second shaft through hole 202 communicates the space surrounded by the shaft cylinder portion 211 and the shaft lid portion 214 with the outside of the shaft 2. As described above, the shaft 2 has the second shaft through hole 202. For example, this space is on the other axial direction D2 side of the shaft lid portion 214 in the hollow portion 212. The second shaft through hole 202 is disposed on the one axial direction D1 side of the first shaft through hole 201 and radially outward of the second shaft 22. In this way, when the shaft 2 rotates, for example, by sucking air from the second shaft through hole 202, the fluid F can be drawn into the inside from the other axial direction D2 side of the first shaft 21 due to the pressure difference. Therefore, the fluid F inside the cylindrical first shaft 21 can be caused to flow out from the first shaft through hole 201 to cool the stator 12 (particularly the coil portion 122).

The second shaft through-hole 202 may be singular or plural. In the latter case, at least some of the second shaft through-holes 202 may be arranged at equal or different intervals in the circumferential direction (see, for example, Figures 6A to 6C described below). In this embodiment, at least some of the second shaft through-holes 202 are arranged in the shaft cover portion 214 and pass through the shaft cover portion 214 in the axial direction.

6A shows a first arrangement example of the second shaft through hole 202 in the shaft cover portion 214. FIG. 6B shows a second arrangement example of the second shaft through hole 202 in the shaft cover portion 214. FIG. 6C shows a third arrangement example of the second shaft through hole 202 in the shaft cover portion 214. At least some of the second shaft through holes 202 may be arranged radially between the radial outer end of the shaft cover portion 214 and the second shaft 22 (see, for example, FIG. 6A). At least some of the second shaft through holes 202 may be arranged along the radial outer side surface of the second shaft 22 (see, for example, FIG. 6B). At least some of the second shaft through holes 202 may be arranged along the radial outer end of the shaft cover portion 214 (see, for example, FIG. 6C). Furthermore, the second shaft through hole 202 arranged along the radial outer end of the shaft lid 214 may be composed of a notch formed in the radial outer end of the shaft lid 214 and a notch formed in the end of the first shaft 21 on one axial side D1.

By arranging at least a portion of the second shaft through-hole 202 in the shaft lid 214, it becomes easier to draw air into the first shaft 21 than when the second shaft through-hole 202 is arranged in the first shaft 21. Furthermore, by providing multiple second shaft through-holes 202 that function as air intakes, the amount of air drawn into the first shaft 21 and the flow of the drawn air can be appropriately adjusted depending on the number and arrangement of the second shaft through-holes 202.

Alternatively, the fluid F flowing on the outside of the shaft cover 214 can be made to flow from the inside of the first shaft 21 to the outside through the second shaft through-hole 202 and supplied to the sealing member 443 described below. Here, if synthetic rubber or the like is used for the sealing member 443, there is a risk that the surface will harden and cracks will occur when the surface dries. Therefore, by supplying the fluid F to the sealing member 443, it is possible to prevent the surface from drying out and suppress cracks caused by hardening. Therefore, the life of the sealing member 443 can be extended.

However, without being limited to the above example, the second shaft through-hole 202 may be disposed in the first shaft 21 and may penetrate the first shaft 21 in the radial direction.

<2-4. Power transmission device 3>
Next, the power transmission device 3 will be described in detail with reference to Fig. 1. The power transmission device 3 is accommodated in a transmission device accommodating space 402 (described later) of the housing 4. The power transmission device 3 has a reduction gear 31 and a differential gear 32.

<2-4-1. Reduction device 31>
The reduction gear 31 is connected to the other axial direction D2 side of the first shaft 21. The reduction gear 31 has a function of reducing the rotational speed of the motor 1 and increasing the torque output from the motor 1 in accordance with a reduction ratio. The reduction gear 31 transmits the torque output from the motor 1 to the drive shaft Ds.

The reduction gear 31 has a main drive gear 311, an intermediate driven gear 312, a final drive gear 313, and an intermediate shaft 314. The torque output from the motor 1 is transmitted to the ring gear 321 of the drive shaft Ds via the shaft 2, the main drive gear 311, the intermediate driven gear 312, the intermediate shaft 314, and the final drive gear 313.

The main drive gear 311 is disposed on the outer circumferential surface of the shaft 2. The main drive gear 311 may be the same member as the shaft 2, or may be a separate member that is firmly fixed. The main drive gear 311 rotates together with the shaft 2 about the rotation axis J1.

The intermediate shaft 314 extends along an intermediate axis J2 parallel to the rotation axis J1. Both ends of the intermediate shaft 314 are supported by a first intermediate bearing 4231 and a second intermediate bearing 4621 so as to be rotatable about the intermediate axis J2. The intermediate driven gear 312 and the final drive gear 313 are disposed on the outer circumferential surface of the intermediate shaft 314. The intermediate driven gear 312 may be the same member as the intermediate shaft 314, or may be a separate member that is firmly fixed.

The intermediate driven gear 312 and the final drive gear 313 rotate integrally with the intermediate shaft 314 around the intermediate axis J2. The intermediate driven gear 312 meshes with the main drive gear 311. The final drive gear 313 meshes with the ring gear 321 of the drive shaft Ds.

The torque of shaft 2 is transmitted from the main drive gear 311 to the intermediate driven gear 312. The torque transmitted to the intermediate driven gear 312 is then transmitted to the final drive gear 313 via the intermediate shaft 314. The torque is then transmitted from the final drive gear 313 to the drive shaft Ds.

<2-4-2. Differential device 32>
The differential device 32 is attached to the drive shaft Ds. The differential device 32 has a ring gear 321. The ring gear 321 transmits the output torque of the motor 1 to the drive shaft Ds. The drive shaft Ds has drive shafts Ds1, Ds2 attached to the left and right sides of the differential device 32, respectively. When the vehicle is turning, for example, the differential device 32 transmits torque to the left and right drive shafts Ds1, Ds2 while absorbing the difference in rotational speed between the left and right drive shafts.

<2-5. Housing 4>
Next, the details of the housing 4 will be described. The housing 4 has a first housing tubular portion 41, a side plate portion 42, a bearing holder 43, a static eliminator holder 44, a cover member 45, and a gear lid portion 46. The first housing tubular portion 41, the side plate portion 42, the bearing holder 43, the static eliminator holder 44, the cover member 45, and the gear lid portion 46 are formed, for example, using a conductive material, and in this embodiment, are formed using a metal material such as iron, aluminum, or an alloy thereof. In addition, in order to suppress bimetallic corrosion at the contact portion, these are preferably formed using the same material. However, this is not limited to the example, and these may be formed using a material other than a metal material, or at least some of these may be formed using a different material.

The housing 4 houses the rotor 11, the stator 12, and the bearings 4211, 431. More specifically, the housing 4 has a motor housing space 401 that houses these. The motor housing space 401 is a space surrounded by the first housing cylindrical portion 41, the side plate portion 42, and the bearing holder 43.

The housing 4 also houses the power transmission device 3. More specifically, the housing 4 has a transmission device housing space 402. The transmission device housing space 402 is a space surrounded by the side plate portion 42 and the gear cover portion 46, and houses the reduction gear 31, the differential gear 32, etc.

A fluid storage section P in which fluid F accumulates is disposed at the bottom of the transmission device housing space 402. A part of the differential device 32 is disposed in the fluid storage section P. The fluid F accumulated in the fluid storage section P is scooped up by the operation of the differential device 32 and supplied to the inside of the transmission device housing space 402. For example, the lower end of the ring gear 321 is immersed in the fluid storage section P. When the ring gear 321 rotates, the fluid F is scooped up by its tooth surface. A part of the scooped up fluid F is supplied to each gear and each bearing of the reduction gear 31 and the differential device 32 in the transmission device housing space 402 and used for lubrication and cooling. In addition, another part of the scooped up fluid F is supplied to the inside of the shaft 2 and supplied to the rotor 11 and stator 12 of the motor 1 and each bearing in the transmission device housing space 402 and used for cooling and lubrication.

<2-5-1. First housing cylindrical portion 41>
The first housing cylindrical portion 41 has a cylindrical shape extending in the axial direction. The motor 1, a reservoir 54 (described later), and the like are disposed inside the first housing cylindrical portion 41. A stator core 121 is fixed to the inner surface of the first housing cylindrical portion 41.

<2-5-2. Side plate part 42>
The side plate portion 42 extends in a direction perpendicular to the rotation axis J1 and covers the end portion on the other axial direction D2 side of the first housing cylindrical portion 41. In this embodiment, the first housing cylindrical portion 41 and the side plate portion 42 are different parts of the same member. By forming the two integrally, the rigidity of these can be increased. However, this is not limited to the example, and the first housing cylindrical portion 41 and the side plate portion 42 may be separate members.

The side plate portion 42 has a side plate through hole 4201 through which the shaft 2 is inserted, and a first drive shaft through hole 4202. The side plate through hole 4201 and the first drive shaft through hole 4202 penetrate the side plate portion 42 in the axial direction. The first shaft 21 is inserted into the side plate through hole 4201. One drive shaft Ds1 of the drive shafts Ds is inserted into the first drive shaft through hole 4202. A seal portion (not shown), such as an oil seal, is arranged in the gap between the drive shaft Ds1 and the first drive shaft through hole 4202 to seal between them.

Note that a seal refers to different components being tightly attached to each other to such an extent that, for example, fluid F inside the components does not leak out, and that foreign matter such as water, dirt, and dust from the outside does not get in. The same applies below to the term seal.

In addition, tightness refers to a level of sealing that prevents the fluid F inside the component from leaking to the outside, and prevents foreign matter such as water, dirt, and dust from entering from the outside. The same applies below to tightness.

The side plate portion 42 further has bearing holders 421, 422, 423, and 424. The bearing holder 421 is disposed on the end surface of the side plate portion 42 on the one axial direction D1 side in the motor housing space 401, and holds the bearing 4211. The bearing holders 422, 423, and 424 are disposed on the end surface of the side plate portion 42 on the other axial direction D2 side in the transmission device housing space 402 described later. The bearing holder 422 is disposed along the outer edge of the end of the side plate through hole 4201 on the other axial direction D2 side, and holds the bearing 4211. The bearing holder 423 holds the first intermediate bearing 4231. The bearing holder 424 is disposed along the outer edge of the end of the first drive shaft through hole 4202 on the other axial direction D2 side, and holds the first output bearing 4241.

<2-5-3. Bearing holder 43>
The bearing holder 43 holds the bearing 431. As described above, the housing 4 has the bearing holder 43. The bearing 431 rotatably supports the shaft 2. The motor 1 includes the bearing 431.

The bearing holder 43 has an opening 432 through which the first shaft 21 is inserted. The opening 432 passes through the bearing holder 43 in the axial direction. As shown in FIG. 2, the bearing holder 43 extends in a direction intersecting the rotation axis J1 (for example, in the radial direction) and covers the end of the first housing cylindrical portion 41 on one axial side D1.

The bearing holder 43 is attached to the end of the first housing tubular portion 41 on one axial direction D1 side. The bearing holder 43 can be fixed to the first housing tubular portion 41 by, for example, fixing with a screw. However, this is not limited to this example, and any method (screwed, press-fit, etc.) that can firmly fix the bearing holder 43 to the first housing tubular portion 41 can be widely used. This allows the bearing holder 43 to be in close contact with the end of the first housing tubular portion 41 on one axial direction D1 side.

<2-5-4. Static electricity removal device holder 44>
The static eliminator holder 44 extends in a direction intersecting the rotation axis J1, and is attached to the end of the bearing holder 43 on one axial direction D1 side. As described above, the housing 4 has the static eliminator holder 44. The static eliminator holder 44 holds the first static eliminator 7 and covers at least a part of the opening 432 of the bearing holder 43. In this embodiment, the first static eliminator 7 is disposed on one axial direction D1 side of the static eliminator holder 44. The first static eliminator 7 electrically connects the second shaft 22 and the static eliminator holder 44. This allows a current generated by a potential fluctuation occurring in the shaft 2 to be discharged to the housing 4 via the first static eliminator 7.

The static eliminator holder 44 also has a plate portion 441, a seal holder 442, and a seal member 443.

<2-5-4-1. Plate portion 441>
2, the plate portion 441 extends in a direction intersecting the rotation axis J1 (for example, in a radial direction). As described above, the static eliminator holder 44 has the plate portion 441. The plate portion 441 is attached to the end portion on one axial direction D1 side of the bearing holder 43. The plate portion 441 forms a space 403 together with the bearing holder 43. In this space 403, a part of the shaft 2 (for example, the end portion on one axial direction D1 side of the first shaft 21), the rotation detector 6, etc. are arranged.

The plate portion 441 has an opening 4411 and a holder recess 4412. The opening 4411 penetrates the plate portion 441 in the axial direction. The second shaft 22 is inserted into the opening 4411. The holder recess 4412 is arranged at the end of the static eliminator holder 44 (particularly the plate portion 441) on one axial direction D1 side. That is, the static eliminator holder 44 has a holder recess 4412. The holder recess 4412 is recessed in the other axial direction D2. At least a part of the first static eliminator 7 is accommodated in the holder recess 4412. By arranging at least a part of the first static eliminator 7 in the holder recess 4412 arranged on the one axial direction D1 side of the static eliminator holder 44, the first static eliminator 7 can be arranged further in the other axial direction D2. Therefore, the axial size of the motor 1 can be reduced, and the motor 1 and the drive device 100 can be made smaller.

In this embodiment, as shown in FIG. 2 and the like, the first static eliminator 7 is spaced apart from the inner surface of the holder recess 4412 facing radially inward. However, the arrangement of the first static eliminator 7 is not limited to this example. For example, as shown in FIG. 7, the first static eliminator 7 (particularly its radially outer end) may be in contact with the inner surface of the holder recess 4412 facing radially inward. In this way, the contact area between the first static eliminator 7 and the static eliminator holder 44 can be made larger. Therefore, the electrical conductivity between the two can be improved. The first static eliminator 7 can also be fitted and fixed between the shaft 2 and the inner surface of the holder recess 4412.

<2-5-4-2. Seal holder 442>
The seal holder 442 is disposed radially outward from the second shaft 22 and holds the seal member 443. As described above, the static eliminator holder 44 has the seal holder 442. In this embodiment, the seal holder 442 is cylindrical and extends in the other axial direction D2 from the end of the plate portion 441 on the other axial direction D2 side. An opening 4411 is disposed radially inward of the seal holder 442 as viewed from the axial direction.

Preferably, the end of the seal holder 442 on the other axial direction D2 side is housed inside the first shaft 21. In this way, the static eliminator holder 44 can be brought closer to the end of the first shaft 21 on the one axial direction D1 side. This allows the axial size of the motor 1 and the drive unit 100 to be reduced. In addition, the fluid F needs to flow between the first shaft 21 and the seal holder 442 before entering between the second shaft 22 and the seal holder 442. In other words, the flow distance of the fluid F can be made longer, making it more difficult for the fluid F to come into contact with the first static eliminator 7.

In addition, the peripheral wall portion 215 is preferably disposed radially outward from the seal holder 442. In this case, the seal holder 442 faces radially from the peripheral wall portion 215 and axially from the end portion on the one axial direction D1 side of the shaft tube portion 211. In this way, the path from the inside of the shaft tube portion 211 to the outside of the shaft 2 between the seal holder 442 and the first shaft 21 can be made longer. Therefore, even if fluid F leaks from the second shaft through-hole 202 disposed in the shaft cover portion 214, for example, the fluid F is less likely to leak to the outside of the shaft 2 through the above-mentioned path.

However, the above example does not exclude a configuration in which the end of the seal holder 442 on the other axial direction D2 side is not housed inside the first shaft 21. For example, the end of the seal holder 442 on the other axial direction D2 side may be separated in the one axial direction D1 from the end of the first shaft 21 on the one axial direction D1 side.

Preferably, the seal holder 442 has a first protruding portion 4421 and a second protruding portion 4422. The first protruding portion 4421 protrudes from the end of the plate portion 441 on the other axial direction D2 side in the axial direction other D2. The second protruding portion 4422 protrudes from the end of the first protruding portion 4421 on the other axial direction D2 side in the axial direction other D2. In this embodiment, the first protruding portion 4421 and the second protruding portion 4422 are each cylindrical extending in the axial direction. The radial outer surface of the second protruding portion 4422 is disposed radially inward from the radial outer surface of the first protruding portion 4421. At least the end of the second protruding portion 4422 on the other axial direction D2 side is inserted into the end of the first shaft 21 on the one axial direction D1 side. In other words, the second protruding portion 4422 is disposed radially inward from the end of the first shaft 21 on the one axial direction D1 side. The end of the first shaft 21 on one axial side D1 faces the first protrusion 4421 in the axial direction and faces the second protrusion 4422 in the radial direction. This makes it possible to lengthen the path from the inside of the first shaft 21 to the outside of the shaft 2 between the seal holder 442 and the first shaft 21. Therefore, even if fluid F leaks from the second shaft through-hole 202 arranged in the shaft cover 214, for example, this fluid F is unlikely to leak to the outside of the shaft 2 through the above-mentioned path.

However, the above example does not exclude a configuration in which the seal holder 442 does not have the second protrusion 4422. For example, as shown in FIG. 8, the seal holder 442 does not exclude a configuration in which the seal holder 442 has only the first protrusion 4421. In this case, the first protrusion 4421 is disposed radially inward from the end of the first shaft 21 on one axial side D1. The first protrusion 4421 axially faces the end of the shaft tube portion 211 on one axial side D1, and radially faces the peripheral wall portion 215.

<2-5-4-3. Sealing member 443>
The seal member 443 is disposed on the other axial direction D2 side of the static eliminator holder 44, and isolates the space in which the first static eliminator 7 is disposed from the fluid F. The motor 1 includes the seal member 443. The seal member 443 seals between the second shaft 22 and the seal holder 442, and is disposed on the other axial direction D2 side of the first static eliminator 7. In this way, the seal member 443 that seals between the second shaft 22 and the seal holder 442 makes it difficult for the fluid that lubricates and cools the stator 12 and the bearing 431 to be applied to the first static eliminator 7. For example, the mist-like fluid F may leak from between the inner and outer rings of the ball bearing 431 or between the bearing 431 and the second shaft 22 through the opening 432 of the bearing holder 43 into the space 403 on the one axial direction D1 side of the bearing holder 43, and may enter between the second shaft 22 and the seal holder 442. The seal member 443 can suppress or prevent the flow of the fluid F by sealing between the second shaft 22 and the seal holder 442. That is, the fluid F is less likely to flow toward the one axial direction D1 than the seal member 443. Also, for example, the fluid F is less likely to leak toward the one axial direction D1 than the static eliminator holder 44. This can suppress or prevent the fluid F from getting onto the first static eliminator 7. Therefore, the motor 1 and the drive device 100 can maintain good electrical connection between the second shaft 22 and the housing 4.

For example, a slinger can be used for the seal member 443. For example, the seal member 443 has a fixed portion (not shown) and a flange portion (not shown). The fixed portion is fixed to the radially outer surface of the second shaft 22. The flange portion extends radially outward from the fixed portion. Alternatively, conversely, the fixed portion may be fixed to the radially inner surface of the seal holder 442. In this case, the flange portion extends radially inward and outward from the fixed portion. The flange portion seals the gap between the second shaft 22 and the seal holder 442. However, the seal member 443 is not limited to this example. The seal member 443 may be an oil seal, a mechanical seal, a packing, or the like.

<2-5-5. Cover member 45>
The cover member 45 is disposed at the end portion on one axial direction D1 side of the static eliminator holder 44. As described above, the housing 4 has the cover member 45. The cover member 45 covers the opening 432 of the static eliminator holder 44 and the first static eliminator 7. The cover member 45 can be attached to the static eliminator holder 44 by, for example, screw fastening, but is not limited to this.

The cover member 45 has a first cover portion 451 and a second cover portion 452. The first cover portion 451 is disposed on the axial side D1 of the opening 432 and the first static eliminator 7, and covers the opening 432 and the first static eliminator 7. The first cover portion 451 has a plate portion 4511. In other words, the cover member 45 has a plate portion 4511. The plate portion 4511 extends in a direction intersecting with the rotation axis J1. The second cover portion 452 is disposed on the axial side D2 and radially outward of the first cover portion 451. The radial inner end of the second cover portion 452 is connected to the radial outer end of the first cover portion 451, and the radial outer end of the second cover portion 452 is connected to the end face of the static eliminator holder 44 on the axial side D1.

The cover member 45 further includes a cover recess 453. The cover recess 453 is recessed from the plate portion 4511 in the other axial direction D2.

The cover member 45 further has a through hole 454. The through hole 454 connects the space surrounded by the static eliminator holder 44 and the cover member 45 with the outside. The through hole 454 may be singular as shown in FIG. 2, or may be multiple. The through hole 454 is arranged in the first cover part 451 in FIG. 2. However, the arrangement of the through hole 454 is not limited to the example shown in FIG. 2. The through hole 454 can be arranged in at least one of the first cover part 451 and the second cover part 452. Alternatively, the through hole 454 may be arranged in the static eliminator holder 44. In other words, the through hole 454 may be arranged in at least one of the static eliminator holder 44 and the cover member 45. In this way, the space between the static eliminator holder 44 and the cover member 45 can be communicated with the outside of this space through the through hole 454. This prevents changes in the internal pressure of this space due to temperature changes, etc., and eliminates the pressure difference between the inside and outside of this space. For example, it is possible to prevent the occurrence of a pressure difference between the axial side D1 and the axial side D2 of the seal member 443, so that it is possible to prevent the fluid F from entering the space between the static eliminator holder 44 and the cover member 45 due to reduced pressure.

The cover member 45 further includes a filter 455. The filter 455 covers the through hole 454. The housing 4 includes a filter 455. The space between the static eliminator holder 44 and the cover member 45 is connected to the outside through the through hole 454 and the filter 455. Preferably, at least one through hole 454 is disposed in the cover recess 453. By covering the through hole 454 with the filter 455, even if wear powder is generated in the first static eliminator 7, the wear powder can be prevented from flying out to the outside through the through hole 454. More preferably, the filter 455 covering the through hole 454 of the cover recess 453 is disposed on the other axial direction D2 than the plate portion 4511. In this way, it is not necessary to secure a space for disposing the filter 455 on the one axial direction D1 side than the plate portion 4511. Therefore, it is possible to prevent an increase in the axial size of the motor 1 and the drive device 100 due to the arrangement of the filter 455.

In this embodiment, the first static eliminator 7 is disposed between the through hole 454 and the filter 455 and the second shaft 22 when viewed from the axial direction. The through hole 454 and the filter 455 are disposed radially outward from the first static eliminator 7. The second shaft 22 is disposed radially inward from the first static eliminator 7. In other words, the through hole 454 and the filter 455 are disposed on the opposite side of the second shaft 22 across the first static eliminator 7. In other words, when viewed from the radial direction, at least a portion of the filter 455 overlaps with the first static eliminator 7. In this way, the filter 455 and the plate portion 4511 of the cover member 45 can be disposed further in the axial direction D2. Therefore, the axial size of the motor 1 and the drive device 100 can be further reduced.

However, the arrangement of the through hole 454 and the filter 455 is not limited to this example. Furthermore, when viewed from the radial direction, at least a portion of the filter 455 does not have to overlap with the first static eliminator 7. When viewed from the axial direction, the through hole 454 and the filter 455 may be arranged on the opposite side of the second shaft 22 from the first static eliminator 7 (see, for example, FIG. 7).

<2-5-6. Gear cover portion 46>
The gear cover 46 is attached to the other axial direction D2 side of the side plate 42. In this embodiment, the gear cover 46 has a plate portion (reference numeral omitted) and a tube portion (reference numeral omitted). The plate portion expands in a direction intersecting with the rotation axis J1. The tube portion is cylindrical and extends from the end portion of the plate portion on the one axial direction D1 side to the one axial direction D1 side. The end portion of the tube portion on the one axial direction D1 side is connected to the side plate portion 42 and is covered by the side plate portion 42. The plate portion and the tube portion, together with the side plate portion 42, form a transmission device housing space 402 in which the power transmission device 3 is disposed. The attachment of the gear cover 46 to the side plate portion 42 can be, for example, fixed by a screw. However, this is not limited to this example, and a wide variety of methods can be used to firmly fix the gear cover 46 to the side plate portion 42, such as screwing or press fitting. This allows the gear cover 46 to be in close contact with the end portion on the one axial direction D1 side of the side plate portion 42.

The gear cover 46 has a second drive shaft through hole 460. The center of the second drive shaft through hole 460 coincides with the differential axis J3 parallel to the rotation axis J1. The other drive shaft Ds2 of the drive shaft Ds is inserted into the second drive shaft through hole 460. A seal part (not shown), such as an oil seal, is arranged in the gap between the drive shaft Ds2 and the second drive shaft through hole 460.

The gear cover 46 further includes bearing holders 461, 462, and 463. The bearing holders 461, 462, and 463 are disposed on the end surface of the gear cover 46 on the other axial direction D2 side in the transmission device housing space 402. The bearing holder 461 holds the bearing 4611. The bearing holder 462 holds the second intermediate bearing 4621. The bearing holder 463 is disposed along the outer edge of the end of the second drive shaft through hole 460 on the other axial direction D2 side, and holds the second output bearing 4631.

The gear lid 46 also has a saucer 464 and an oil passage 465. The saucer 464 is disposed on the end face of the gear lid 46 on one axial side D1, and has a recess that is recessed vertically downward. The saucer 464 can store the fluid F scooped up by the ring gear 321. The oil passage 465 is a passage for the fluid F, and connects the saucer 464 to the inlet 213 of the shaft 2. The fluid F stored in the saucer 464 is supplied to the oil passage 465 and flows into the hollow portion 212 from the inlet 213 at the end on the other axial side D2 of the shaft 2.

<2-7. Fluid circulation section 5>
The fluid circulation unit 5 supplies the fluid F contained in the housing 4 to the stator 12 and the bearings 4211, 431, etc. The fluid circulation unit 5 has a piping unit 51, a pump 52, a cooler 53, and a reservoir .

The piping section 51 connects the pump 52 and the reservoir 54, and supplies the fluid F to the reservoir 54. The pump 52 sucks the fluid F stored in the lower region of the transmission device housing space 402. The pump 52 is an electric pump, but is not limited to this. For example, the pump 52 may be configured to be driven by using part of the power of the shaft 2 of the drive device 100.

The cooler 53 is disposed between the pump 52 and the reservoir 54 of the piping section 51. That is, the fluid F sucked by the pump 52 passes through the cooler 53 via the piping section 51 and is then sent to the reservoir 54. The cooler 53 is supplied with a refrigerant, such as water, supplied from the outside. The cooler 53 exchanges heat between the refrigerant and the fluid F to lower the temperature of the fluid F.

The reservoir 54 is a tray capable of storing fluid F, and is accommodated in the motor accommodating space 401 of the housing 4, which will be described later. Inside the motor accommodating space 401, the reservoir 54 is disposed vertically above the stator 12. A drip hole 540 is formed in the bottom of the reservoir 54, and the motor 1 is cooled by dripping fluid F from the drip hole 540. The drip hole 540 is formed, for example, above the coil end 1221 of the coil portion 122 of the stator 12, and the coil portion 122 is cooled by the fluid F.

<2-8. Rotation detector 6>
The rotation detector 6 detects the rotation angle of the shaft 2. In this embodiment, the rotation detector 6 is a resolver having a resolver rotor and a resolver stator. The rotation detector 6 has a resolver rotor (not shown) fixed to the shaft 2, and a resolver stator (not shown) fixed to one axial side of the bearing holder 43 of the housing 4. The resolver rotor and the resolver stator are annular. The inner peripheral surface of the resolver stator faces the outer peripheral surface of the resolver rotor in the radial direction. The resolver stator periodically detects the rotation angle position of the resolver rotor when the rotor 11 rotates. In this way, the rotation detector 6 obtains information on the rotation angle position of the rotor 11. It should be noted that the present embodiment is not limited to the example, and the rotation detector 6 does not have to be a resolver, and may be, for example, a rotary encoder.

The rotation detector 6 is disposed in a space 403 surrounded by the bearing holder 43 and the static eliminator holder 44. In this way, it is not necessary to secure space to place the rotation detector 6 on one side of the axial direction D1 from the static eliminator holder 44. Therefore, it is possible to suppress an increase in the axial size of the motor 1 and the drive unit 100.

<2-9. First static eliminator 7>
5A and 5B , the configuration of the first static eliminator 7 will be described. The first static eliminator 7 is fixed to the housing 4 and contacts the shaft 2. The first static eliminator 7 electrically connects the shaft 2 and the housing 4. In this embodiment, the first static eliminator 7 is disposed on one axial side D1 of the static eliminator holder 44 and contacts the radially outer surface of the second shaft 22.

As shown in FIG. 5A (and FIG. 2), the first static eliminator 7 of this embodiment has a conductive member 71, an elastic member 72, a holding member 73, and a fixing member 74.

The conductive member 71 is formed using a material having electrical conductivity. The tip of the conductive member 71 contacts the second shaft 22. In this embodiment, the conductive member 71 is a molded body, but is not limited to this example, and may be in the shape of a brush made of bundled carbon fibers or the like. The conductive member 71 is preferably made of a material with good sliding properties, and more preferably of a material with a low coefficient of friction. The conductive member 71 may be made of a composite resin containing a conductive filler such as carbon fiber or metal, for example.

The elastic member 72 is housed in a compressed state inside the holding member 73. Due to its elasticity, the elastic member 72 pushes the conductive member 71 toward the second shaft 22. In this embodiment, a spring coil is used as the elastic member 72, but it is not limited to this example and other types of members such as a leaf spring or rubber may be used.

The holding member 73 is a bottomed cylinder, and houses a part of the conductive member 71 and the elastic member 72 inside. The holding member 73 holds the conductive member 71. In detail, the holding member 73 holds the end of the conductive member 71 on the elastic member 72 side so that it can move in the direction in which the holding member 73 extends. The holding member 73 also holds the elastic member 72 so that it can expand and contract in the direction in which the holding member 73 extends.

The fixing member 74 fixes the first static eliminator 7 to the housing 4. In this embodiment, the fixing member 74 fixes the first static eliminator 7 to the static eliminator holder 44 (see, for example, FIG. 5A). However, this is not limited to the example, and the fixing member 74 may fix the first static eliminator 7 to the cover member 45. In other words, the fixing member 74 can fix the first static eliminator 7 to at least one of the static eliminator holder 44 and the cover member 45.

The fixing member 74 is conductive and is electrically connected to the conductive member 71. The fixing member 74 is fixed to the conductive static eliminator holder 44 or the cover member 45, so that the conductive member 71 is electrically connected to the housing 4.

In this embodiment, as shown in FIG. 5A, the first static eliminator 7 (the conductive member 71) contacts a part of the circumferential area of the radial outer surface of the second shaft. However, this is not limited to the example, and the first static eliminator 7 (the conductive member 71) may contact the entire circumferential area of the outer surface of the second shaft 22 as shown in FIG. 5B. In other words, the first static eliminator 7 (the conductive member 71) only needs to contact at least a part of the circumferential area of the radial outer surface of the second shaft 22. By the first static eliminator 7 contacting at least a part of the circumferential area of the radial outer surface of the second shaft 22, whose outer diameter is smaller than that of the first shaft 21, the sliding area of the first static eliminator 7 against the second shaft 22 per rotation of the shaft 2 can be made smaller. Therefore, the wear powder generated at the contact portion between the first static eliminator 7 and the shaft 2 can be reduced.

3. Modifications
Next, a first modified example to a third modified example of the embodiment will be described with reference to Figs. 9 to 11. Fig. 9 is a conceptual diagram showing an enlarged configuration example of the main parts of the drive device 100 according to the first modified example. Fig. 10 is a conceptual diagram showing an enlarged configuration example of the main parts of the drive device 100 according to the second modified example. Fig. 11 is a conceptual diagram showing an enlarged configuration example of the main parts of the drive device 100 according to the third modified example. Note that Figs. 9 to 11 are merely conceptual diagrams, and the arrangement and dimensions of each part are not necessarily the same as those of the actual drive device 100. Also, Figs. 9 to 11 correspond to the enlarged views of the portion II surrounded by the dashed line in Fig. 1.

The above-described embodiment and the first to third modified examples can be implemented in any suitable combination as long as no particular contradiction arises.

<3-1. First modified example>
A first modified example will be described with reference to Fig. 9. Note that the following describes the configuration of the first modified example that is different from the above-mentioned embodiment. Also, the same components as those in the above-mentioned embodiment are given the same reference numerals, and the description thereof may be omitted.

In the first modified example, the motor 1 further includes a second static eliminator 8. The second static eliminator 8 electrically connects the first shaft 21 and the housing 4. In this way, the current generated by the potential fluctuation occurring in the shaft 2 can be discharged to the housing 4 via the second static eliminator 8. Therefore, the static elimination efficiency of the shaft 2 can be further improved.

The second static eliminator 8 is fixed to the bearing holder 43 on the one axial direction D1 side. The second static eliminator 8 is disposed on the other axial direction D2 side of the end of the first shaft 21 on the one axial direction D1 side. In FIG. 9, the second static eliminator 8 contacts a part of the circumferential area of the radial outer surface of the first shaft 21. However, this is not limited to the example, and the second static eliminator 8 may contact the entire circumferential area of the radial outer surface of the first shaft 21. In this way, it is not necessary to secure a space for arranging the second static eliminator 8 on the one axial direction D1 side of the first shaft 21. Therefore, it is possible to suppress an increase in the axial size of the motor 1 and the drive device 100. This contributes to the miniaturization of the motor 1 and the drive device 100.

In this embodiment, the configuration of the second static eliminator 8 is the same as that of the first static eliminator 7, but is not limited to this example and may be different from that of the first static eliminator 7.

<3-2. Second modified example>
Next, a second modified example will be described with reference to Fig. 10. Note that the following describes the configuration of the second modified example that is different from the above-mentioned embodiment and the first modified example. Also, the same reference numerals are used to designate the same components as those in the above-mentioned embodiment and the first modified example, and the description thereof may be omitted.

In the second modified example, the seal holder 442a is a recessed portion disposed on the other axial side D2 of the static eliminator holder 44, and is recessed in one axial direction. The seal holder 442a is also separated in one axial direction D1 from the end portion on the one axial direction D1 side of the first shaft 21. The seal member 443 is disposed on the inner surface of the seal holder 442a that faces radially inward.

Therefore, the first shaft 21 does not have a peripheral wall portion 215, and the end portion on one axial direction D1 side of the shaft tube portion 211 becomes the end portion on one axial direction D1 side of the first shaft 21. In addition, the shaft cover portion 214 is disposed at the end portion on one axial direction D1 side of the first shaft 21.

According to the second modified example, the axial distance between the end of the first shaft 21 on one axial direction D1 side and the static eliminator holder 44 can be made narrower. Therefore, the axial size of the motor 1 and the drive device 100 can be made smaller.

<3-3. Third modified example>
Next, a third modified example will be described with reference to Fig. 11. Note that the following describes the configuration of the third modified example that is different from the above-mentioned embodiment, first modified example, and second modified example. Also, the same reference numerals are used to designate components that are the same as those in the above-mentioned embodiment, first modified example, and second modified example, and descriptions thereof may be omitted.

In the third modified example, the first static eliminator 7 is disposed between the second shaft 22 and the seal holder 442, on one side of the axial direction D1 from the seal member 443. This arrangement also more reliably suppresses or prevents the fluid F from coming into contact with the first static eliminator 7.

In the third modified example, the first static eliminator 7 is disposed on the other axial direction D2 side of the static eliminator holder 44. Therefore, the end of the second shaft 22 on the one axial direction D1 side can be disposed on the other axial direction D2 side of the plate portion 441. Also, as shown in FIG. 11, the opening 4411 and the holder recess 4412 do not have to be disposed on the plate portion 441 of the static eliminator holder 44. Furthermore, by omitting the opening 4411, the cover member 45 can also be omitted. In this way, the number of parts of the housing 4 can be reduced and the static eliminator holder 44 can be made to have a simpler configuration. Furthermore, since the arrangement of the parts on the one axial direction D1 side of the static eliminator holder 44 can be omitted, the axial size of the motor 1 and the drive device 100 can be reduced.

In the third modified example, the first static eliminator 7 is a conductive bearing lubricated by a lubricant 75 having a higher electrical conductivity than the fluid F. In this embodiment, the lubricant 75 is a conductive grease. In the conductive grease, a conductive material such as copper powder or carbon powder is added to a lubricating oil such as grease. The first static eliminator 7 can electrically connect the second shaft 22 and the static eliminator holder 44 by the lubricant 75. In FIG. 11, the first static eliminator 7 is a ball bearing lubricated by the lubricant 75. The inner ring of the first static eliminator 7 is fixed to the radial outer surface of the second shaft 22, and the outer ring of the first static eliminator 7 is fixed to the radial inner surface of the seal holder 442. In this case, the inner ring and the outer ring of the first static eliminator 7 are electrically connected by the lubricant 75, so that the second shaft 22 is electrically connected to the seal holder 442 of the static eliminator holder 44.

The first static eliminator 7 is also arranged coaxially with the bearing 431. For example, they are both annular and centered on the same axis (i.e., the rotation axis J1). In this way, the first static eliminator 7, together with the bearing 431, can more stably support the shaft 2 for rotation.

11 does not exclude a configuration in which the first static eliminator 7 is not a conductive bearing. In the third modified example, the first static eliminator 7 contacts the entire circumferential area of the radially outer surface of the second shaft 22, but is not limited to this example and may contact only a partial circumferential area of the radially outer surface of the second shaft 22. The first static eliminator 7 may be fixed to one of the second shaft 22 and the seal holder 442, or may contact the other. For example, the first static eliminator 7 may be configured as shown in FIG. 5A or FIG. 5B.

＜4. Other＞
The embodiments of the present invention have been described above. Note that the scope of the present invention is not limited to the above-described embodiments. The present invention can be implemented by adding various modifications to the above-described embodiments without departing from the spirit of the invention. Furthermore, the matters described in the above-described embodiments can be appropriately combined in any manner as long as no contradiction occurs.

The present invention is useful for devices that ground shafts.

100: Drive device, 200: Battery, 300: Vehicle, 1: Motor, 11: Rotor, 111: Rotor core, 1111: Rotor through hole, 112: Magnet, 12: Stator, 121: Stator core, 122: Coil portion, 1221: Coil end, 2: Shaft, 201: First shaft through hole, 202: Second shaft through hole, 21: First shaft, 211: Shaft cylinder portion, 212: Hollow portion, 213: Inlet, 214: Shaft cover portion, 215: Peripheral wall portion, 216: Step, 2161: First opposing surface, 2162: Second opposing surface, 22: . . . Second shaft, 3... Power transmission device, 31... Reduction gear, 311... Main drive gear, 312... Intermediate driven gear, 313... Final drive gear, 314... Intermediate shaft, 32... Differential device, 321... Ring gear, 4... Housing, 401... Motor accommodating space, 402... Transmission device accommodating space, 403... Space, 41... First housing cylindrical portion, 42... Side plate portion, 4201... Side plate through hole, 4202... First drive shaft through hole, 421, 422, 423, 424... Bearing holding portion, 4211... Bearing, 4221... Bearing, 4231... First intermediate Bearing, 4241...first output bearing, 43...bearing holder, 431...bearing, 432...opening, 44...static charge removal device holder, 441...plate portion, 4411...opening, 4412...holder recess, 442, 442a...seal holder, 4421...first protrusion, 4422...second protrusion, 443...seal member, 45...cover member, 451...first cover portion, 4511...plate portion, 452...second cover portion, 453...cover recess, 454...through hole, 455...filter, 46...gear cover portion, 460...second drive shaft through hole, 461, 462, 46 3: Bearing holder, 4611: Bearing, 4621: Second intermediate bearing, 4631: Second output bearing, 464: Receptacle, 465: Oil passage, 5: Fluid circulation section, 51: Pipe section, 52: Pump, 53: Cooler, 54: Reservoir, 540: Drip hole, 6: Rotation detector, 7: First static eliminator, 71: Conductive member, 72: Elastic member, 73: Holding member, 74: Fixing member, 75: Lubricant, 8: Second static eliminator, F: Fluid, P: Fluid storage section, Ds, Ds1, Ds2: Drive shaft, J1: Rotating shaft, J2: Intermediate shaft, J3: Differential shaft

Claims (18)

a shaft having a first shaft extending axially along a rotation axis;
a rotor fixed to the shaft and rotatable about the rotation axis;
a stator facing the rotor with a radial gap therebetween;
A bearing that rotatably supports the shaft;
a housing that accommodates the rotor, the stator, and the bearing;
A first static eliminator;
A seal member;
Equipped with
The shaft further includes a second shaft extending in one axial direction from the first shaft,
The housing includes:
a bearing holder having an opening through which the first shaft is inserted and configured to hold the bearing;
a static eliminator holder that holds the first static eliminator and covers at least a portion of the opening;
having
the static eliminator holder has a seal holder disposed radially outward from the second shaft and configured to hold the seal member;
the first static eliminator electrically connects the second shaft and the static eliminator holder;
The seal member seals between the second shaft and the seal holder, and is disposed on the other axial side of the first static electricity removal device. The motor according to claim 1, wherein the first static eliminator is disposed either on one axial side of the static eliminator holder or on one axial side of the seal member between the second shaft and the seal holder. The outer diameter of the second shaft is smaller than the outer diameter of the first shaft,
The motor according to claim 1 or 2, wherein the first static eliminator is in contact with at least a partial area in a circumferential direction of a radially outer surface of the second shaft. the static eliminator holder further includes a plate portion extending in a direction intersecting the rotation axis,
The seal holder includes:
a first protruding portion protruding in the other axial direction from the other axial end portion of the plate portion;
a second protruding portion protruding in the other axial direction from the other axial end portion of the first protruding portion;
and
the second protruding portion is disposed radially inward from one axial end portion of the first shaft,
The motor according to claim 1 , wherein one axial end of the first shaft faces the first protruding portion in the axial direction and faces the second protruding portion in the radial direction. The motor according to any one of claims 1 to 4, wherein the other axial end of the seal holder is housed inside the first shaft. The first shaft is
a cylindrical shaft portion extending in an axial direction and surrounding the rotation shaft;
a shaft cover portion disposed on one axial side of the cylindrical shaft portion;
having
The shaft is
a first shaft through hole that radially penetrates the first shaft;
a second shaft through hole that communicates a space surrounded by the shaft tube portion and the shaft cover portion with the outside of the shaft;
and
The motor according to claim 1 , wherein the second shaft through hole is disposed on one axial side of the first shaft through hole and radially outward of the second shaft. The second shaft extends in one axial direction from the shaft cover portion,
The motor according to claim 6 , wherein at least a portion of the second shaft through hole penetrates the shaft cover portion. the first shaft further includes a peripheral wall portion protruding in one axial direction from one axial end portion of the cylindrical shaft portion,
The peripheral wall portion is disposed radially outward from the seal holder,
The motor according to claim 7 , wherein the seal holder faces the peripheral wall portion in a radial direction and faces one axial end portion of the cylindrical shaft portion in an axial direction. The first shaft further has a step into which the shaft cover portion fits,
The step is
a first opposing surface that axially faces the other axial end portion of the shaft cover;
a second opposing surface that extends in one axial direction from a radial outer end portion of the first opposing surface and radially faces the radial outer end portion of the shaft cover;
9. The motor according to claim 6, further comprising: A rotation detector for detecting a rotation angle of the shaft is further provided.
The motor according to claim 1 , wherein the rotation detector is disposed in a space surrounded by the bearing holder and the static eliminator holder. The motor according to claim 1 , further comprising a second static eliminator electrically connecting the first shaft and the housing. The motor according to claim 11, wherein the second static eliminator is disposed axially further away from one axial end of the first shaft than the other axial end of the first shaft. the first static eliminator is disposed on one axial side of the static eliminator holder,
the static eliminator holder further has a holder recess recessed in the other axial direction,
The motor according to claim 1 , wherein at least a portion of the first static eliminator is accommodated in the holder recess. The motor according to claim 13, wherein the radially outer end of the first static eliminator contacts the inner surface of the holder recess facing radially inward. the housing further includes a cover member disposed at one axial end of the static eliminator holder to cover the first static eliminator and the opening,
The motor according to claim 1 , wherein at least one of the static eliminator holder and the cover member has a through hole. The housing further includes a filter covering the through hole.
a space between the static eliminator holder and the cover member is connected to the outside via the through hole and the filter;
The cover member is
A plate portion extending in a direction intersecting the rotation axis;
a cover recess recessed from the plate portion in the other axial direction;
having
At least one of the through holes is disposed in the cover recess;
The motor according to claim 15 , wherein the filter covering the through hole of the cover recess is disposed on the other side of the plate portion in the axial direction. the first static eliminator is disposed on one axial side of the static eliminator holder,
The motor according to claim 16 , wherein at least a portion of the filter overlaps with the first static eliminator when viewed in a radial direction. A motor according to any one of claims 1 to 17;
a power transmission device that transmits the power of the motor to a drive shaft;
A drive unit comprising: